Diarrhea, a disease with many causes

Diarrhea describes the condition of having frequent, loose and watery stool, often caused by an infection of the gut.

Diarrhea is the passage of 3 or more loose or liquid stools per day, or more frequently than is normal.1 Diarrhea is usually short - term condition and the recommanded treatment approach is rehydratation and to manage and reduce the symptoms until it resolves.2

What causes diarrhea?

Diarrhea can be caused by many different factors including:2

Infections of the intestine by bacteria or viruses

Taking certain medications, for example antibiotics

An intolerance to particular foods

Particular digestive diseases, such as irritable bowel syndrome and some other diseases

Stress or poor diet

All of these can disturb the balance of the microbiota and stimulate the cells in the gut to release excessive fluid.3 This disturbance of the microbiota is called dysbiosis, and if it is not corrected can have consequences on health, as the microbiota may be less effective in protecting the intestine against gastrointestinal infections, and less effective in stimulating the immune system.4,5

Repeated infections of the gastro - intestinal tract (gastroenteritis), may result in a chronic disturbance of the microbiota, and this can increase the risk of developing certain diseases, such as inflammatory bowel disease.6

‘Biotics’ can reduce the frequency and help thicken the stool. ‘Biotics’ can also help to restore the natural balance of the microbiota.7-9
A healthy, diverse microbiota helps and protects against diarrhea, it helps to prevent infection, reinforces the immune system and improves absorption of nutrients.10 If the microbiota remains unbalanced for a long period of time, it may increase the risk of some diseases.6

Diarrhea in children, a serious risk of dehydration

The most serious consequence of diarrhea in children is dehydration. The symptoms of dehydration in babies and children can include thirst, dry mouth, reduced tears, less urine, drowsiness and irritability. In very dehydrated babies and children the skin becomes looser and eyes appear sunken.9 The child may also have fever, chills and blood in the stool. These later signs are indicative of a viral or bacterial infection of the intestine. Rotavirus infections, for example, are very common causes of diarrhea in children.9 If the diarrhea lasts longer than 24 hours in a child, a doctor should be contacted.

Diarrhea in adults, can be acute or chronic

In adults, diarrhea may be acute, lasting a couple of days, or chronic, lasting more than two weeks.11

  • Acute diarrhea is usually a result of a gastrointestinal infection, and may also accompanied with symptoms like nausea, vomiting, abdominal pain, cramps, bloating, an increase in stool frequency, and a loss of bowel control.11
  • Chronic diarrhea is less likely to have an infectious cause and may be associated with immune - related diseases of the gut, such as Crohn’s disease, irritable bowel syndrome or ulcerative colitis.

Depending on the duration of therapy, many medications and therapies may have a diarrhea side - effect.

What does treatment involve?

When active treatments are required to manage diarrhea, the goals of these treatments are to:5

In all cases of acute diarrhea the most urgent treatment is rehydration. This can be achieved by drinking enough fluids if the person with diarrhea is only mildly dehydrated, or for rapid rehydration where salts have been lost, oral rehydration salt solutions can be used. These are water, sugar and electrolyte (potassium and sodium salts) solutions than help to rapidly restore liquids and electrolytes to the blood. In cases requiring hospitalization the electrolyte solutions can be infused.

Having something bland and carbohydrate - rich to eat may also help to restore nutrients, calm the intestine and thicken the stool. Probiotics and Postbiotics can reduce the frequency and improve stool consistency. ‘Biotics’ also restore the balance of the microbiota which have positive impact on health.

In the case of acute bacterial infections, with diarrhea resulting from bacterial gastroenteritis, antibiotics may be prescribed to stop the infection.5 However antibiotics could cause imbalance in the microbiota, and thus can be the cause of the diarrhea itself, as well as other gastrointestinal problems – these effects may also be long - term.11

  1. Diarrhoeal diseases. World Health Organization, 2017. (Accessed December 2020, at https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease).
  2. Diarrhea. Also called: dysentery, the runs, the trots. National Institutes of Health/US National Library of Medicine, 2020. (Accessed August 2020, at https://medlineplus.gov/diarrhea.html#.)
  3. König J, Wells J, Cani PD, et al. Human intestinal barrier function in health and disease. Clin Transl Gastroenterol 2016;7:e196.
  4. Binder HJ. Pathophysiology of acute diarrhea. Am J Med 1990;88:2s-4s.
  5. Barr W, Smith A. Acute diarrhea. Am Fam Physician 2014;89:180-9.
  6. Weiss GA, Hennet T. Mechanisms and consequences of intestinal dysbiosis. Cell Mol Life Sci 2017;74:2959-77.
  7. Szajewska H, Guarino A, Hojsak I, et al. Use of probiotics for management of acute gastroenteritis: a position paper by the ESPGHAN Working Group for Probiotics and Prebiotics. J Pediatr Gastroenterol Nutr 2014;58:531-9.
  8. Guarino A, Ashkenazi S, Gendrel D, Lo Vecchio A, Shamir R, Szajewska H. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/European Society for Pediatric Infectious Diseases evidence-based guidelines for the management of acute gastroenteritis in children in Europe: update 2014. J Pediatr Gastroenterol Nutr 2014;59:132-52.
  9. Farthing M, Salam MA, Lindberg G, et al. Acute diarrhea in adults and children: a global perspective. J Clin Gastroenterol 2013;47:12-20.
  10. Thursby E, Juge N. Introduction to the human gut microbiota. Biochem J 2017;474:1823-36.
  11. Riddle MS, DuPont HL, Connor BA. ACG clinical guideline: diagnosis, treatment, and prevention of acute diarrheal infections in adults. Am J Gastroenterol 2016;111:602-22.

Self - care : ideas & advice

In the case of acute diarrhea, irrespective of the cause, making sure to keep hydrated and getting adequate nutrition are essential first steps…

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